Trajectory Tracking for Unmanned Aerial Vehicles using Nonlinear H_∞ Approach

The purpose of this paper is the three-dimensional guidance tracking of an unmanned aerial vehicle using robust nonlinear control strategy. For this purpose, the model of the reference tracking error is produced first, and using Lyapunov stability guidance commands are then provided. Terms of the Lyapunov equation is exponentially stable, partly by adding a set of disturbance variables to the input error state variables and Developing a virtual dynamic system, the stabilization and disturbance rejection is provided using nonlinear H∞ strategy. In order to apply this strategy and avoid the complexity of the problem, the inverse optimality approach is used to derive the controller. Finally, the stabilizer control added to guidance commands, and the Lyapunov stability of the whole system from optimality perspective due to the minimization of a cost function is provided. The simulation results indicate that by using this algorithm, the UAV follows the flight trajectory as well.